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Forum: Pentax SLR Lens Discussion 12-06-2019, 07:03 AM  
Samyang 135 2.0
Posted By Gimbal
Replies: 14
Views: 792
Yes, but you should know that the image quality is not comparable to the 135. Not even close.
Forum: Pentax K-1 11-14-2019, 02:28 AM  
Pixel Shifted Images
Posted By Gimbal
Replies: 1,291
Views: 148,599
I guess noise level can be improved in areas without any details, such as in a blue sky for instance, even if the camera moves slightly. The motion detection algorithm has nothing to detect motion from so the four individual pictures will all be used with a cleaner image as a result.

If Rawtherapee still detects motion in those areas (which can happen due to false triggering on noise) adjust the settings until you get a good compromise.
Forum: Pentax K-1 11-04-2019, 01:59 AM  
Brand new K1 with a moving part inside it
Posted By Gimbal
Replies: 44
Views: 2,135
Yes, that is how it works. The earlier models K10d to K5 did not activate the SR mechanism until you fully pressed the shutter button so the sensor was free to rattle around until only a few milliseconds before the shutter opened, and as soon as the shutter closed the SR system was deactivated and the sensor dropped down again. The K1 as you have noticed picks up the sensor already at half press, (a faint electronic humming can be heard.) and drops it like an anchor after timeout.
Forum: Pentax K-1 11-02-2019, 02:32 AM  
Brand new K1 with a moving part inside it
Posted By Gimbal
Replies: 44
Views: 2,135
Exactly, some people just does not pick up on subtle things, at all.
This is a Pentax thing in all their DSLRs since the K10d, the sensor is loose and can move around up/down and left right a few mm. Some cameras might need a little bump for the sensor to shift, others slide more easily. Nothing to worry about.
Forum: Pentax K-1 10-28-2019, 03:14 AM  
Pentax's "Shake Reduction" Goes Crazy With Mirrorless Lenses
Posted By Gimbal
Replies: 14
Views: 954
The big difference here is that it is only the later models (after the K5 or so) that has SR active in such a way that it moves the sensor as soon as you halfpress the shutter button. The earlier models did not activate the sensor coils until the mirror started to flip up, thus there is no active movement inside the K10D until you actually take the picture.
Forum: Pentax SLR Lens Discussion 08-25-2019, 01:10 PM  
lens light-gathering abilities
Posted By Gimbal
Replies: 284
Views: 8,114
Earth is round, everyone knows that. Just like a Pizza.
Forum: Pentax SLR Lens Discussion 08-24-2019, 04:30 AM  
lens light-gathering abilities
Posted By Gimbal
Replies: 284
Views: 8,114
I have not mentioned "optical" enlargement or talked about pixel sizes at all. That is all you. I'm in the total sensor area camp. The bigger the better, the number of pixels are not that important but usually the more the merrier.

---------- Post added 08-24-2019 at 01:35 PM ----------



No, that is down sampling. You reduce the number of pixels to fit the output device, it has nothing to do with size.
Maybe it will fit perfectly on a 24" screen, or a 5" phone, or a bill board, who knows? Size is not involved.
Forum: Pentax SLR Lens Discussion 08-24-2019, 04:04 AM  
lens light-gathering abilities
Posted By Gimbal
Replies: 284
Views: 8,114
Luckily you don't have to understand it, and you don't have to know the original size of the sensor to print at whatever size you choose.
And no, the computer does not need to know the original size either, but that does not mean that there isn't ratio of enlargement involved and that this ratio effects the outcome.

However, everyone does know by experience that an APS-C sensor prints bigger then a phone sensor. And most people know that a FF prints better then a crop sensor, and FF is beaten by a MF. But that is all a coincidence of course. :)
Forum: Pentax SLR Lens Discussion 08-23-2019, 08:11 PM  
lens light-gathering abilities
Posted By Gimbal
Replies: 284
Views: 8,114
Same Tech level, but to make it easier let's say a K1 in crop mode and a K1 in full frame mode. Enlarge both images 20 times and the center crop rectangle will be identical.
Forum: Pentax SLR Lens Discussion 08-23-2019, 10:13 AM  
lens light-gathering abilities
Posted By Gimbal
Replies: 284
Views: 8,114
The center part of the printed images will be of similar quality. Perhaps even Identical.
Forum: Pentax SLR Lens Discussion 08-23-2019, 09:56 AM  
lens light-gathering abilities
Posted By Gimbal
Replies: 284
Views: 8,114
I can see your point, it's just bunch of numbers and size doesn't really matter any more.

But here is the thing, it did matter when the image was created, which means it will matter when you print it.

Lets say you have an APS-C sensor 24mm wide, you take a picture and enlarge it 20 times (just tag a long for a while) the print is 20*24=480mm wide. And you are very picky so you don't want to print bigger because noise and crap turns up.

Now take the same image with at 36mm wide sensor (of equal quality, only bigger, same exposure), and you will be able to enlarge it 20 times as well, ending up with at 20*36= 720mm wide image before the noise and crap turns up.

So size matters.
Forum: Pentax SLR Lens Discussion 08-23-2019, 09:02 AM  
lens light-gathering abilities
Posted By Gimbal
Replies: 284
Views: 8,114
Oh but there is. The image is there during the exposure, and as soon as the shutter closes the sensor starts to convert it into digital numbers. The size of the image is the same as the size of the sensor.
It's comparable to a film that is later feed through a scanner and digitized, we just skip the film part and digitize immidiately.
Forum: Pentax SLR Lens Discussion 08-23-2019, 06:19 AM  
lens light-gathering abilities
Posted By Gimbal
Replies: 284
Views: 8,114
What? 100% isn't a size.
It doesn’t work that way since pixels doesn’t have a commonly agreed upon size.

---------- Post added 08-23-2019 at 03:39 PM ----------

Dont mix the number of pixels making up an image, with the size of the image. Its two different things.

An image can be enlarged at the same time as the number of pixels used can be reduced. It is still enlarged.
A photo printed two by two meter can be down sampled to 10x10 pixels, it is still enlarged, even though pretty much all information is lost.
Forum: Pentax SLR Lens Discussion 08-23-2019, 04:14 AM  
lens light-gathering abilities
Posted By Gimbal
Replies: 284
Views: 8,114
It has now been stated by everyone, pixels are not used to measure size. Right, keep that in mind for the rest of this post. Pixels are not .

So take for example an image projected on a 35mm frame/sensor and then viewed on a 24 screen.
Has the image size been reduced? (Remember, pixels are NOT a measurement of size, millimeter are.)

It has been enlarged.


If we now take an image from a APS-C sensor and display it on the same 24 screen, it has to be enlarged even more then the FF image to fill the screen. ENLARGED, even though it was down sampled. Pixels are NOT used to measure size.
Forum: Pentax SLR Lens Discussion 08-22-2019, 02:22 AM  
lens light-gathering abilities
Posted By Gimbal
Replies: 284
Views: 8,114
Or People who thinks that noise performance per pixel is all that matters are like people who think that the number of horsepower is all that matters when it comes to go fast.

“Look,” they say, “this truck has 600 horse powers, it’s much faster than the small BMW with only 340 horse powers”.

But they are wrong.
Forum: Pentax SLR Lens Discussion 08-21-2019, 01:48 AM  
lens light-gathering abilities
Posted By Gimbal
Replies: 284
Views: 8,114
Right, everyone agrees on that.




Sort of, it’s the size of the lens that does it. And a larger sensor needs a larger lens.
A phone lens with an aperture of 1.8 does not collect as much light as a FF lens with the same aperture. That is why the FF sensor will beat the phone in dark situations. The same goes for binoculars, a large front lens will give you a brighter image. And yes, it’s not magic. The more photons you collect, the better the image.
Forum: Pentax SLR Lens Discussion 08-20-2019, 09:04 AM  
lens light-gathering abilities
Posted By Gimbal
Replies: 284
Views: 8,114
It is far from irrelevant, when creating a photo you better collect as much light as possible, thus total amount of light used to create the image is very relevant.

But of course if the FF sensor is inferior to the APS-C sensor then that might even the playing field but one has to assume "all else equal" when comparing, there is no point comparing if you change every parameter at once.
Forum: Pentax SLR Lens Discussion 08-20-2019, 05:19 AM  
lens light-gathering abilities
Posted By Gimbal
Replies: 284
Views: 8,114
There are two questions:
I use a light meter and it says shoot the scene @ f2.4 Would I get approximately the same expo with a FF & APS-C body?

The answer is yes.


And the other question:
When using my SMC Pentax 55mm F1.8 @ 1.8 on a APS-C camera does that sensor get approximately the same amount of light as using it on a FF @ the same f:stop?

The answer is no, the lens projects an evenly lit image (vignette aside) but the APS-C sensor only captures the light in the center while the FF sensor being larger pics up more of the projected image.

So its the large bucket vs the small bucket again (note that the large bucket isnt necessarily deeper, but it has a larger opening). More photons are picked up by the larger sensor, simply because it is larger. And more photons equals better SNR and better image quality.
Forum: General Photography 08-15-2019, 11:06 AM  
Does greater sensor "real estate" equate to better image quality?
Posted By Gimbal
Replies: 107
Views: 4,512
But microlenses can move that point somewhat.

Or isn't that used anymore?:confused:
Forum: General Photography 08-15-2019, 05:18 AM  
Does greater sensor "real estate" equate to better image quality?
Posted By Gimbal
Replies: 107
Views: 4,512
And they are right, image size is measured in mm, cm, inch or similar. You are talking about up/down sampling of the number of pixels used, and that is not connected to size at all.
Forum: Pentax K-1 07-25-2019, 01:34 AM  
Shutter shock with small primes
Posted By Gimbal
Replies: 62
Views: 4,873
What do you mean, why would it be pointless?:confused:
Forum: Pentax Full Frame 07-12-2019, 01:14 AM  
Why are FF images so much more pleasing than APS-C?
Posted By Gimbal
Replies: 259
Views: 25,197
Is that also a scientific fact?
:confused:
Forum: Pentax K-1 07-03-2019, 03:49 AM  
K1 - Pixel Shift & Bracketing - Question
Posted By Gimbal
Replies: 16
Views: 4,679
Interesting, do you have any examples from the comparison left?
Forum: Pentax K-1 07-01-2019, 03:23 AM  
K1 - Pixel Shift & Bracketing - Question
Posted By Gimbal
Replies: 16
Views: 4,679
Then you were doing something wrong.
A 16 bit TIFF can hold A LOT more info than an eight bit jpeg.
Forum: Pentax K-1 05-23-2019, 11:43 AM  
Post your K-1 pictures!
Posted By Gimbal
Replies: 27,926
Views: 2,443,527
Taking a stroll in the woods.
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